In the related art, there is a seat sliding device for a vehicle that includes a lower rail configured to be fixed to a vehicle floor and an upper rail which slidably engages with the lower rail and supports a seat upward. In such a seat sliding device, drive force from a motor or the like as a drive source enables the upper rail to slide with respect to the lower rail in a vehicle frontward-rearward direction.
For example, JP 2010-06122A (Reference 1) discloses a seat sliding device that includes a screw rod supported by an upper rail in a rotatable manner and a nut member fixed to a lower rail. The seat sliding device has a configuration in which the screw rod screwed into the nut member is driven by drive force.
Further, the seat sliding device disclosed in Reference 1 includes a fixing portion fixed to the upper rail, a bearing (cylinder portion) provided at one end of the screw rod, and an elastic body (eccentricity absorbing leg) that connects the fixing portion and the bearing. In such a configuration, eccentric rotation of the screw rod is absorbed through elastic deformation of the elastic body.
In addition, JP 2011-31667A (Reference 2) discloses a seat sliding device in which a nut member is fixed to a lower rail via a fixing bracket. Further, a damper made of an elastic body is interposed between the nut member and the fixing bracket. In such a configuration, the damper absorbs vibration generated from a drive source.
Incidentally, as described above, in the configuration in which the screw rod screwed into the nut member rotates, problems arise in that an axis line of the screw rod is inclined with respect to an axis line of a screw hole provided in the nut member, so-called “skewness” occurs, and thereby “defective mesh” is performed between the nut member and the screw rod. However, in a structure in which eccentric rotation or vibration of the screw rod is absorbed by using the elastic body like the related art, it is not possible to solve such problems in some cases. In this manner, there is a concern that a smooth operation of the screw rod is interrupted.
Thus, a need exists for a vehicle seat sliding device which is not susceptible to the drawback mentioned above.